1. Field of the Invention
The present invention relates to an audio amplifier circuit and a method of the same, especially to an amplifier circuit that dynamically adjusts an audio output signal and a method of the same.
2. Description of Related Art
Along with fast development of modern technology, the design of audio output devices has become more precise. For providing users high quality sounds, manufacturers develop various types of audio output devices, each of which focused on specific sound field.
However, most of the audio output devices available now have problems of distortion and noises. The distortion causes voices output by the audio output devices changes while the noises have negative effect on the playback quality of the audio output devices. In order to reduce negative effects of the distortion and the noises on the output voices, designers have tries in different ways.
In an amplifier circuit of the audio output device available now, both a pre-gain value and a post-gain value are fixed values, unable to be adjusted after the audio output device being manufactured. When users adjust the output volume level into low level or high level, the conventional amplifier circuit amplifiers noises or causes distortion of audio output signals. Thus an audio output signal generated by the conventional amplifier circuit that amplifies the audio input signal by the fixed gain value also comprises the amplified noises or distortion. Therefore the playback quality of the audio output device is reduced. The design of conventional amplified circuit leads to limited playback quality of the audio output device and users can't have better listening quality.
Thus there is room for improvement and a need to provide an audio amplifier circuit that overcomes shortcomings of conventional amplifier circuit of audio output devices such as distortion and noise problems.